The Influence of N,N-Dimethylformamide on Dispersion of Multi-Walled Carbon Nanotubes

Abstract

Preparation of highly homogeneous disperse ions multi-walled carbon nanotubes (MWCNTs) has vital effect on their applications. In this research, the ultrasonication and heat treatment were used to prepare suspensions of MWCNTs using N,N-dimethylformamide (DMF) as dispersant innovatively. The suspensions were characterized by UV–Vis absorbance spectroscopy, adsorption isotherm, transmission electron microscopy, atomic force microscope and fourier transform infrared. The experimental results showed that the optimum concentration of DMF was 0.9 g/L, the best sonication time was 30 min and the optimum temperature was 50°C; The TEM and AFM images showed that the agglomeration of bundles was broken up, and the thickness of MWCNTs decreased because of the incorporation of DMF. In addition, the dispersing mechanism is that molecules of DMF get into the space of MWCNTs bundles to break up the aggregation, and amide groups of DMF easily form intermolecular hydrogen bonds to decrease surface tension. Using DMF to disperse MWCNTs had a remarkable effect, dispersed MWCNTs may be added into cement-based materials or other composite materials to improve their performance.